Integrated lead or wireless suspensions and flexures (i.e., suspension components) are used to support read/write transducers in disk drives or other dynamic data storage systems. Flexures of type used in connection with disk drive head suspensions are generally known and commercially available. These devices typically include leads or traces formed in a copper or other conductive material layer over a stainless steel or other spring metal layer. A layer of dielectric insulating material such as polyimide separates the traces from the spring metal layer. The flexures are mounted to other components such as a stainless steel load beam in one embodiment of the invention. Subtractive and/or additive processes such as photolithography, wet and dry etching and deposition processes can be used to fabricate the flexures.
Plated ground features are often incorporated into disk drive head suspension flexures. These ground features are, for example, used to electrically interconnect the traces though apertures in the dielectric insulating layer to the underlying stainless steel layer. For example, they can be used to electrically interconnect so-called interleaved traces through the stainless steel layer. Ground features of these types and associated methods of manufacture are disclosed, for example, in the Tronnes U.S. Pat. No. 7,875,804 and the Peltoma U.S. Pat. No. 7,384,531.
The copper or other conductive material of the traces to which the ground features are connected are often plated with relatively non-corrosive materials such as NiAu (nickel-gold). NiAu does not, however, adhere well to stainless steel. A plated ground feature must therefore be large enough (e.g., in diameter) to cover the aperture through the insulating layer and the portion of the stainless steel layer exposed by that aperture. Furthermore, because of the need to accommodate layer-to-layer misregistration due to limitations inherent in the photolithography and deposition processes used to form ground features, the ground features are typically made even larger than the insulating layer apertures.
There remains, however, a continuing need for smaller ground features which can reduce the space taken up by the ground features to allow for other features to also be used and/or miniaturization of the assemblies.